The present invention relates to an alarm system for alarming a clog of a fuel injector nozzle used in an engine for a motor vehicle.
In a known fuel injection system, a fuel injector is provided in an intake manifold so as to inject fuel into cylinders. Further, in order to provide charge stratification in the cylinder and ensure stable combustion in light and middle load ranges of engine operations, the engine with a direct fuel injection system is currently developed. In the system, the fuel is directly injected into a combustion chamber of the cylinder.
The fuel injector injects the fuel from the nozzle in accordance with a fuel injection pulse width signal fed from a fuel injection control system.
In the direct fuel injection system, since the nozzle of the fuel injector is exposed in the combustion chamber, the nozzle is liable to be clogged with carbon sticking thereto.
In order to solve the problem, in the former system where the fuel is injected into the intake manifold, it has been proposed to provide at least two fuel injectors in order to prevent reduction of fuel injection quantity caused by the nozzle clog. Japanese Patent Applications Laid-Open 60-67745, 60-79135, and 60-93152 disclose such a system.
However, in the direct fuel injection system, it is difficult to provide space for the two fuel injectors in each cylinder. If the nozzle of the fuel injector is clogged with carbon, the quantity of the fuel reduces. In the worst case, the fuel injection stops and the engine stalls.